south africans are preparing for public services for nelson mandela this week. president obama leaves this morning for johannesburg where he'll attend tomorrow's massive public memorial. former presidents bush, clinton, and carter will also be in attendance along with 50 heads of state, making it one of the world's largest gathers in recent history. >> this is a test for us. >> reporter: the national task force says the country is prepared for keeping so many dignitaries safe. 11,000 soldiers have been set in place around the country to protect the mourners. >> we believe people will be watching the house of africa when we perform. >> reporter: this makeshift memorial outside of nelson mandela's former home in sweto is one of places where mourners have gathered. for a day of prayer. south africans of all races and religious backgrounds sang and praised for a man credited with united a country once bitterly divided. >> nelson mandela, this is a man who fought for me when i was not born yet. >> reporter: mandela's ex-wife winnie was among those attending the praye